1. Field of the Invention
The present invention pertains to magnetic tape of the type employed for transducing information, and particularly to such magnetic tape having a leader for securing the magnetic tape to a reel hub.
2. Related Art and Other Considerations
Manufacturers of magnetic tape cartridges (also known as magnetic tape cassettes) have historically and traditionally constructed the tape portion of the cartridge in the manner illustrated in FIG. 1. In particular, a small piece of adhesive-coated tape 20 (sometimes referred to as a "splicing tape" or "splice tape"has been used in a lap joint configuration to join magnetic tape 22 to a leader 24. The leader 24 attaches to a reel hub 26 around which the tape is to be wound.
Unfortunately, the presence of the splicing tape creates "bumps" B or "print-throughs" in the tape pack as shown in FIG. 2. As additional tape layers are wound on hub 26, the inward pressure increases on the inner layers, and the stress in the magnetic tape 22 at the discontinuities attributable to the splicing tape-created bumps B at the angular positions indicated by arrows 32. The stress may be high enough to create permanent deformations in the magnetic recording tape. These deformations appear as two vertical folds in the magnetic tape. The deformations remain (and can even become permanent) after the magnetic tape has been unwound from the reel hub, as illustrated by deformations 34 in FIG. 3. The permanent deformations are greatest in the first outer tape layer adjacent to the splicing tape, and can persist for many layers.
The deformations occasioned by the prior art splicing tape create undesired signal losses when a transducing head attempts to record or reproduce information with respect to the magnetic tape. The signal losses are attributable, at least in part, to the increased head-to-tape spacing with both helical and longitudinal recording methods. Areas of the magnetic tape having the permanent deformations may be rendered unusable.
FIG. 4 shows the usual prior art situation in which the splicing tape 20 is vertically oriented, e.g., has splicing tape ends 20.sub.E which are perpendicular to the elongated edges 36 of the magnetic recording tape 22. In this prior art vertical orientation, for helical scan recording the deformations occasioned by the splicing tape cut across many data tracks or stripes. The helical data tracks are inclined at an angle with respect to the splicing tape ends 20.sub.E, as exemplified by track 38 in FIG. 4, due to the fact, e.g., that a transducing head on a recording scanner or drum travels across the tape at a shallow angle. When the deformations or print-throughs are vertically oriented in the manner depicted by FIG. 4, they can affect (e.g., render unusable) many data tracks.
What is needed, therefore, and an object of the present invention, is a way to minimize or counteract the deformations occasioned by a splicing tape which joins magnetic recording tape to a leader or trailer.